(Scott Sommerdorf | Tribune file photo) The Salt Lake City Council on Tuesay enacted changes to allow new accessory dwellings to be built more widely in residential areas across the city. John Armstrong, who hopes to build one on his mother’s property, posed in December next to her home near the site of the proposed dwelling. Based on a study of similar zoning changes in Portland and Denver, city planners estimate the new approach to ADUs could lead to between four and 25 new dwellings being built annually in Salt Lake City.

In its push to address affordable housing, the Salt Lake City Council voted Tuesday to loosen zoning rules on so-called mother-in-law apartments with hopes of opening up new, smaller dwellings across the city’s residential neighborhoods.

A common feature of the city’s housing stock decades ago, so-called accessory dwelling units — basement apartments, ones inside or above garages and those in separate buildings in yards — have for years been limited in Utah’s capital to locales a half-mile or less from Salt Lake City’s TRAX stops.

But after years of debate and public input, the City Council voted 5-1 late Tuesday to approve zoning changes that essentially allow such dwellings citywide, although with some conditions on permitting in certain areas dominated by single-family homes. Only Councilman Charlie Luke was opposed, calling the new rules “unenforceable.”

The city’s new approach also eases some requirements on entrances and setbacks for ADUs, as well as rules for parking by letting driveways and available street parking spaces suffice.

The new rules would require that a property owner live in either the accessory dwelling or the main residence, a move planners said was designed to curtail private absentee owners from buying up ADUs as commercial rentals. Accessory dwelling owners also would be licensed by the city.

The changes are welcomed by many city residents as a way of easing an ongoing housing crunch and helping give homeowners new flexibility. But many other residents have been deeply opposed, warning that large numbers of new pocket dwellings could disrupt parking and the quality of life in established residential areas.

Council Chairwoman Erin Mendenhall urged passage of the changes and praised her colleagues for the “blood, sweat and tears” in analyzing city policy on ADUs over the years. She said the issue not only centered on housing affordability but also would allow residents to “age in place” and not be forced to move as their housing needs change.

“This is not about cheap apartments created overnight, but rather access to housing for the longer term,” Mendenhall said.

After hearing public testimony Tuesday, Councilman Derek Kitchen rejected staff recommendations to delay final approval of the ADU changes for further review. He asked colleagues to overlook uncertainties and approve the measure, “see how it shakes out in our community” and then revisit the ordinance in a few years.

“This will not fix the affordable housing crisis,” but it was worth trying, Kitchen said, even if the dwellings it added to the housing market pushed down rents “only nominally.”

Councilman Chris Wharton said new ADUs spurred by the changes could also provide housing for students, young professionals and lower-income residents in “higher-opportunity” neighborhoods that were safer, had better schools and offered historic character.

Based on a study of similar zoning changes in Denver and Portland, planners estimate they could spur construction of between four and 25 new ADUs per year in Salt Lake City neighborhoods. Officials expect the first ADUs created under the new ordinances to be in homes, although the new rules cover attached and detached dwellings.

But Luke said that after years of discussion, the new rules remained too vague and “had the potential to drastically change the look and feel of neighborhoods.”

“In nine years [of debate],” Luke said, “nobody has been able to tell me how this is going to be enforced and how we’re going to protect the neighborhoods we have.”